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Researchers Create Silicon-Based Quantum Bit

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  • by Anonymous Coward

    Seems like a bit of waste !!

    • Re: (Score:3, Insightful)

      by Anonymous Coward

      so did a single vacuum tube when that was first invented...

      • by mcgrew (92797) *

        The difference being that you can't do anything with a single bit, although this will of course lead to better things, but a single vaccuum tube, a diode, wire, and a speaker will make a radio (without the tube you need headphones). A single vaccuum tube is an amplifier..

        • by Chris Burke (6130)

          A single vaccuum tube is an amplifier.

          So's a single transistor.

          Both become "bits" only when you choose to interpret their outputs as binary.

          • by mcgrew (92797) *

            I'm not talking about bits, I'm talking about sound amplification. You can hook an input to a tube's cathode, a speaker to its anode, a power source to its heater, and it will amplify the input. You need at least two transistors to do that.

            • by Chris Burke (6130)

              Ah, so saying "bit" was a typo. Okay. Anyway, you only need one transistor to make a linear amplifier.

    • Not necessarily but it begs the question, has anyone gotten one of these to "go fast" yet? They're supposed to be some kind of magical unlimited 2-state ultimate binary data processing device. I think I heard that got one to add like 1 + 1 or something but has anyone else gotten one to run at like an equivilant of 1GHz yet?
  • Useful links (Score:5, Informative)

    by hweimer (709734) on Thursday September 20, 2012 @05:36AM (#41396933) Homepage
  • Bit not a Qubit (Score:5, Informative)

    by Big Hairy Ian (1155547) on Thursday September 20, 2012 @05:45AM (#41396973)
    All this demonstrates is the ability to store 1 bit of information at the atomic level not a Qubit which can be in multiple states at once due to quantum entanglement. This is like heralding the dawn of the computer age by promoting a mechanical calculator.
    • Re:Bit not a Qubit (Score:5, Informative)

      by hweimer (709734) on Thursday September 20, 2012 @05:53AM (#41397001) Homepage

      They show relatively clear Rabi oscillations [wikipedia.org], which are a definite proof of the quantumness of the evolution of their system (which has nothing to do with entanglement). So, yes, this is a genuine qubit, albeit not a perfect one.

    • by Anonymous Coward on Thursday September 20, 2012 @06:29AM (#41397121)

      No, they've demonstrated a single Qubit.

      TFS makes things mucky by mentioning single electron transistors too, which are a completely different beast.

      The problem with quantum computing isn't demonstrating single qubits though. The problem is in getting a reasonable number in a superposition. Most I've ever seen in a QC that actually does computations is 7 qubits.

      Just to get an idea of the scale we need, Shor's algorithm, the one which we could use to crack RSA encryption in polynomial time, needs 2*N qubits minimum. So to crack RSA1024 we'd need 2048 qubits all in a state of superposition.

      I'm of the opinion adding more qubits to a superposition is going to be an exponentially hard problem.

      • Re: (Score:2, Interesting)

        by hweimer (709734)

        I'm of the opinion adding more qubits to a superposition is going to be an exponentially hard problem.

        History tells otherwise. [quantenblog.net]

        • by js33 (1077193)
          ... based on a grand total of seven data points, and not controlled for the amount of resources that went into achieving an ever-so-brief superposition of, so far, no more than 14 or 15 qubits. The article you linked is very appropriately and clearly not much more than a scientifically excited suggestion that the growing number of qubits is in an exponential trend, and a guess at what might happen if the assumed trend should continue. You've got nerve to say "History tells otherwise." "History" also tell
    • quantum entanglement != superposition
    • by Bigby (659157)

      So at some level we will be able to store more than off/on information? How many states can we expect? 3? 10?

      • by jbo5112 (154963)

        A qbit is a quantum binary digit, so there will only two states by definition. Otherwise, it's not a binary digit. Eventually, we might find a way to pack more than 1 qbit per physical device, but we're having enough trouble just getting a usable number of qbits.

        On the other hand, regular transistors are a technology that is quite mature, and most people don't realize they're actually analog devices. We just pick a threshold current, where anything above is on and anything below is off, in order to make

      • by mcgrew (92797) *

        So at some level we will be able to store more than off/on information?

        You could do that now, but you would need a completely new archetecture. You could have a three state machine, positive, negative, and off. It would work in trinary rather than binary (000 001 002 010 011 012 020 021...)

        back in the fifties through seventies they had "infinite state" analog computers in many universities. I built a primitive one when I was 12 (more of an electric slide rule than a computer). But the big fancy ones did rea

        • by Bigby (659157)

          I have often thought of the ternary/trinary architecture with the positive/negative/off or a no charge, half charge, full charge type of breakdown.

          An infinite state medium of storage increases chances for corruption. I was wondering if there are multi-state quantum particles at the atomic or subatomic level. That would make for REALLY small mediums of storage. A 100-state subatomic particle would result in TBs of storage in the smallest imaginable locations.

          • by Chris Burke (6130)

            I have often thought of the ternary/trinary architecture with the positive/negative/off or a no charge, half charge, full charge type of breakdown.

            That makes the circuits much harder to design.

            For traces that are short enough that you can just treat them as capacitive/resistive loads rather than transmission lines, the nice thing about a binary circuit is that you just drive the output towards one of the two voltage rails. Driving it harder just gives you the result you want faster, or drive it slower if that's okay.

            With a 3-rail circuit there would be plenty of situations where driving too fast towards the middle rail would result in reading '0' or

  • by Anonymous Coward

    ...not phosphorous. That's something different.

    Geez. For a geek site, I'd expect better. Just look up in Wikipedia if unsure.

  • provides little details on how it was done. I suspect an incremental but important improvement being hyped as revolutionary.

  • can you run linux on it?
  • ...or some other quantum computer programming language.

    (Of course, I suppose that to really do quantum software development correctly, you have to learn to be great at it and totally suck at the same time. Well, at least while no one's watching...)

  • ... that the Core i7 processor containing 731,000,000 transistors weighs approximately 386 g. 731,000,000 Silicon atoms weighs roughly 34 fg (femtograms) - using Avogadro's Constant and assuming I did my calculation correctly. That's a pretty huge space savings, even if you were only using binary computation.
    • ... that the Core i7 processor containing 731,000,000 transistors weighs approximately 386 g. 731,000,000 Silicon atoms weighs roughly 34 fg (femtograms) - using Avogadro's Constant and assuming I did my calculation correctly. That's a pretty huge space savings, even if you were only using binary computation.

      ...and then it got hot and separated the atoms too far from each other to interact. D'oh!

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